Glossary

Use this glossary of common hydroponic terms and get up to speed.

  • The offspring from two plants of different breeds, variety or genetic make-up.

  • Instantly soluble lime, used to raise or lower ph.

  • One of several brand names/varieties of clay aggregate medium (also known as LECA for light expanded clay aggregate). It is a lightweight, porous substrate with excellent aeration. Because it does not really wick water effectively, Geolite and other LECA mediums are favorites in ebb-and-flow and drip hydroponic systems.

  • An instrument for measuring relative humidity in the atmosphere.

  • A portion of a plant stem between nodes.

  • This micronutrient acts as a catalyst in the photosynthesis/respiration process, and is essentialp for the formation of sugars and starches. Iron also activates certain other enzymes.

  • A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-coa derived from carbohydrates, fats and proteins into carbon dioxide and chemical energy.

  • Leaf malformation due to overwatering, over fertilization, lack of magnesium, insect or fungus damage or negative tropism.

  • The primary nutrients N-P-K or the secondary nutrients magnesium and calcium.

  • This micronutrient activates one or more enzymes in fatty acid synthesis; it also activates the enzymes responsible for DNA and RNA production. Closely associated with copper and zinc, manganese also participates directly in the photosynthetic creation of oxygen from water.

  • The substrate or soilless material which supports the plant and absorbs and releases the nutrient solution in hydroponic horticulture.

  • Also referred to as trace elements, including S, Fe, Mn, B, Mb, An and Cu.

  • This micronutrient is essential for nitrogen fixation and nitrate reduction.

    Basics
  • The dying of plant tissue, usually the result of serious nutrient deficiency or pest attack.

  • A hydroponic method in which nutrient is fed into grow tubes or trays in a thin film where the roots draw it up. This “nutrient film” allows the roots to have constant contact with the nutrient and the air layer above at the same time.

  • A system in which the roots of a plant are consistently or intermittently misted with fine droplets of nutrient solution.

  • The function of this micronutrient is not well understood, but it is suspected that it might aid carbohydrate transport.

  • Leaf tips that turn dark from excess fertilizer and salt burn.

  • This micronutrient is essential for photosynthesis, where it acts as an enzyme activator during the production of oxygen from water.

  • The condition of a sick plant with yellowing leaves due to inadequate formation of chlorophyll. Chlorosis is caused by a nutrient deficiency, usually iron or nitrogen; nutrient deficiencies are themselves often caused by a ph that is out of the acceptable range.

  • A plant produced through asexual reproduction including, but not limited to, cuttings, layering and tissue culture.

  • To soak new Rockwool in an acidic solution to lower the ph from 8.0 to 5.5.

  • This micronutrient is an internal catalyst and acts as an electron carrier; it is also believed to play a role in nitrogen fixation.

  • Disease that attacks young seedlings and cuttings, causing stems to rot at the base; overwatering is the main cause of damping-off.